The present invention relates to methods and apparatus for rapidly heating semiconductor wafers.
Advances in processing of integrated circuit devices, in particular, devices of decreased dimensions, have necessitated the development of new processing and manufacturing techniques. One of the strictest requirements imposed by the tight tolerances on the dimensions of such devices has been the need to restrict the amount of time an integrated circuit device is subjected to high temperatures. This has led to the development of a rapid thermal process step, whereby the semiconductor device is irradiated with an optical source powerful enough to quickly raise the temperature of the semiconductor device to the desired process temperature and hold it at that temperature for a sufficient time to accomplish a specific process step.
In order to carry out such a rapid thermal processing step in a production environment, the heating of the semiconductor wafer must be uniform. As the speed of heating is increased, the nonuniformity of the heating is accentuated. In addition, the nonuniformity of heating may vary depending upon the size of the wafer. Finally, a heating pattern which may be desirable for one process step may be undesirable for another process step.